Improvement in furnaces for roasting ores



UNITEIJ STATEs PATENT OFFICE.

RICHARD` F. KNOX AND JOSEPH OSBORN, OF SAN FRANCISCO, CALIFORNIA.

IMPROVEMENT lIN FURNACES FOR ROASTING ORES.

Specication forming part of Letters Patent No. 117,430, dated July 25, 1871 g antedated July 5, 1871.

To all whom it may concern:

. Be itknown that we, RICHARD F. KNOX and JOSEPH OSBORN, Of the city and county of San Francisco, State of California, have invented certain new and useful Improvements in Roasting-Furnaces; and we do hereby declare the following description and accompanying drawing are sufficient to enable any person skilled in the art or science to which it most nearly appertains to make and use our said invention or improvements without further invention or experiment.

Our invention relates more especially tO a furnace for which Letters Patent were granted to us dated June 15, 1870.

In this f'urnace a series of gratings or pigeon holes allows the heat to pass from the furnace to the Ore-chamber, and on the Opposite side a similar series of pigeon-holes gives egress to the fumes and volatile products of the roasting. As the furnace is lilled with ore a difficulty arises,

which is that the finer portions of the Ore grad! ually work into the pi, ;eonholes and fill them up. furnace with a series of vertical arches, each lower arch receding from the one above, so that the angle will be greater than the slope at which the ore will lie, thus preventing the iillin g up of the passages. Our invention further relates to a device for feeding to the lire the brush or chapcwfral used for fuel, and which burns with so in tense a heat and ilame that a body Of it must be introduced a-nd the door closed almost instantaneously.

Referring to the accompanying drawin g, A is the fire-place, and B the rore-chamber of the furnace. In the present drawing only one side Of the chamber is provided with arches, but in .actual construction the arches take the place of the pigeonholes on both sides, as shown in the former patent. The upper arches a, on Opposite sides, are brought as near together as the desired dialneter Of the chamber at that point. The next arch b will recede from the base of the first about seven nches, or sufficiently to make a line drawn be- In Order to prevent this we construct theV tween its upper edge and the base of the arch a stand at an angle less than the natural slope of the Ore as it lies in the chamber. rlhe passages c, between thearches on this side, serve to admit the heat from the lire-place, while those on the other side allow the volatile products to pass Off. The remaining arches below b, as d of, each recede from the one above, so that when the furnace is filled -with Ore it can in no case rise so high as to clog the passages c. Any suitable number Of' arches may be employed, as the necessities of the work require. The feeding device for the fire consists of a short trough or tray, g, which is constructed with a bottom and sides but no ends, and of such a size as to just enter the fire-door h. This troughis suspended byrods i or suitable devices from above, as at m, so that, after being filled with chcqxwral, it can be drawn away from the door, which is then opened. The trough is allowed to swing back to the opening, and the load is instantly forced in and the door closed, thus preventing the flames from coming out, which would be the case in any other manner ofl feeding. The eye o serves to attach a rope for drawing the trough away Or for raising it Out of' the way when not needed.

Having thus described our invention, we desire to secure by Letters Patent* l. The ore-chamberB havin gthe vertical arches c b d e, with the passages c at the base of each, when constructed to recede from each other, sub stantially as and for the purpose herein described. 2. The feeding device, consisting of the trough g suspended by the rods i, when constructed and operated substantially as herein described.

In witness that the above-described invention is claimed by us we have hereunto set our hands.

EIO'EAED E. KNOX. JOSEPH OsBOEN.

Witnesses:

GEO. H. STRONG, JOHN L. BOONE. 

